# CVE-2026-54902: ruby-oj: Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem

CVE-2026-54902 is fixed in ruby-oj on 1 platform, first by DEBIAN-CVE-2026-54902, released July 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-54902
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0050
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 1, 2026

## Description

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, is vulnerable to Use-After-Free when in SAJ mode. The Oj::Parser does not protect cached object keys (≥ 35 bytes) from garbage collection, and a Ruby callback that triggers GC inside hash_end can cause the key string to be reclaimed while the C parser still holds a pointer to it. The subsequent access to the freed string VALUE results in a segfault, confirmed by an RIP pointing to address 0x4242 (a canary-style pattern suggesting control over the freed memory's content). This issue has been fixed in version 3.17.2.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | ruby-oj Debian 12.15 (bookworm) | 3.14.2-1+deb12u1 | [DEBIAN-CVE-2026-54902](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54902.md) | Jul 3, 2026 |
| Linux | ruby-oj Debian 13.5 (trixie) | 3.16.3-1+deb13u1 | [DEBIAN-CVE-2026-54902](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54902.md) | Jul 3, 2026 |
| Linux | ruby-oj Debian 14 | 3.17.6-2 | [DEBIAN-CVE-2026-54902](https://patchblox.com/security/data/fix/linux/debian-cve-2026-54902.md) | Jul 3, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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